How should an American man dress in public?

I have of course noticed that in Saudi Arabia women generally dress in black and men dress in white.  I am wondering what the expectation is for how a foreign man should dress in public.  Should I wear a white shirt?  I like to wear colorful Hawaiian shirts on the weekend and I'm wondering if this would be ok.  I will dress in whatever way is most appropriate, I just need some suggestions on what is acceptable.

I hope you remember me. My friend, we are not here in middle ages. you can dress what you like anytime, simply because you are a man :(. Just keep in your mind to avoid the extreme short shorts in public places like the markets and malls.
Enjoy your life here since you are a man. About ladies God helps them to get rid of bad habits here.
I hope you enjoy your stay here in WONDERLAND !!

U can wear anything of any colour but not shorts or innerwears in public...

All respect, but I'm wearing CHINO SHORTS AND SPORT SHORTS in public without any problem.

Thank you for your replies, that is very good news.  I will not wear any very short shorts!